Leak detection system and method for tube or catheter placement

ABSTRACT

The present disclosure relates to a leak detection system and method for tube or catheter placement. The system and method includes acoustically sensing a leak in the seal between a tube or catheter within a body and the body cavity against which it is sealed, assisting the user in adjusting the system until the leak has been substantially sealed, and establishing system parameters to be used thereafter to maintain the system in an operating state that will substantially prevent leakage, all using a noninvasive acoustic technique.

I. CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 13/783,916, filed Mar. 4, 2013, now U.S. Pat. No. 9,498,590, issuedNov. 22, 2016, which claims the benefit of U.S. Provisional ApplicationNo. 61/606,679, filed Mar. 5, 2012, each of which are incorporatedherein by reference.

II. FIELD

The present disclosure is generally related to a leak detection systemand method for tube or catheter placement.

III. DESCRIPTION OF RELATED ART

Endotracheal tubes (hereinafter “ETTs”), often referred to as breathingtubes, are used to provide a conduit for mechanical ventilation ofpatients with respiratory or related problems. An ETT is insertedthrough the mouth or nose and into the trachea of a patient for severalreasons: (1) to establish and maintain an open airway; (2) to permitpositive pressure ventilation which cannot be done effectively by maskfor more than brief periods; (3) to seal off the digestive tract fromthe trachea thereby preventing inspiration of forced air into thestomach; and (4) as an anesthesia delivery system.

ETTs are used extensively in the field, emergency rooms, surgicalsuites, and intensive care units for patients that require ventilatoryassistance. During intubation, an ETT is typically inserted into themouth, past the vocal cords, and into the trachea. The proper locationof the ETT tip is roughly in the mid-trachea. However, there are atleast three possible undesired placement positions that can result,either during intubation or due to a subsequent dislodgment. One ofthese positions is in the esophagus. Another undesired position occursfrom over-advancement of the ETT past the bifurcation of the trachea(carina) and into one of the mainstem bronchi. A third is above thevocal cords in the vocal tract.

The structure of the human airways is extremely complex. At the upperend of the trachea is the larynx containing the vocal folds, and at thelower end is the first bifurcation, known as the carina. The adulttrachea is approximately 1.4 to 1.6 cm in diameter and 9 to 15 cm long.The newborn trachea averages about 0.5 cm in diameter and 4 cm inlength. The airways that are formed by the carina are the right primarybronchus and the left primary bronchus. The right primary bronchus isshorter, wider, and more vertical than the left primary bronchus. Forthis reason a majority of erroneous ETT insertions past the carina tendto follow the right primary bronchus. Continuing farther down theairways, the bronchi branch into smaller and smaller tubes. They finallyterminate into alveoli, small airfilled sacs where oxygen-carbon dioxidegas exchange takes place.

Providing a correctly positioned and unobstructed endotracheal tube is amajor clinical concern. Any misplacement or obstruction of an ETT canpose a threat to the patient's health. Misdirecting the ETT into theesophagus or locating the tip where there is a significant obstructionof its lumen can result in poor ventilation of the patient andeventually lead to cardiac arrest, brain damage or even death. Further,if the ETT is misplaced into a mainstem bronchus, lung rupture canoccur.

In an attempt to avoid possible complications with Err use, severaltechniques have been developed to aid clinicians in the properplacement/location of ETTs. Guidelines for the ideal technique are asfollows: (1) the technique should work as well for difficult intubationsas it does for those not so difficult; (2) the technique should indicatea proper ETT tip location unequivocally; (3) esophageal intubation mustalways be detected; and (4) clinicians must understand the technique andhow to use it. The known techniques for clinical evaluation of ETTlocation include direct visualization of the ETT placement, chestradiography, observation of symmetric chest movements, auscultation ofbreath sounds, reservoir bag compliance, the use of a video stethoscope,fiberoptic bronchoscopy, pulse oximetry, and capnometry. However, noneof the listed techniques allow a health care provider to constantlymonitor the precise location of an ETT within the trachea, or the degreeof obstruction of its lumen.

Another challenge with placing the ETT in the trachea for ventilation isan undesirable backflow of air around the ETT, since such backflowreduces the amount of positive ventilation pressure that can bemaintained in the lungs. To address this challenge, a cuff can beadapted to seal against the inner diameter of the trachea. However, asthe tracheal walls move, leaks can still occur. In addition,post-placement movement of the ETT within the trachea can also causeleaks around the ETT. In some embodiments, the cuff may be inflated witha fluid (such as air) in order to form the seal. A cuff pressure that istoo high can collapse the blood capillaries in the wall of the tracheaand cause necrosis. A cuff pressure that is too low may provide aninadequate seal and result in both a reduction of positive ventilationpressure and an increased likelihood of fluid from the proximal side ofthe cuff (such as accumulated patient secretions) to leak into thelungs, raising the possibility of the patient contracting pneumonia.

Apparatuses and methods for acoustically guiding, positioning, andmonitoring tubes within a body are known in the art. See, for example,U.S. Pat. Nos. 5,445,144 and 6,705,319 to Wodicka et al., incorporatedherein by reference, which disclose an apparatus and method foracoustically monitoring the position of a tube within an anatomicalconduit. In various embodiments, a sound pulse is introduced into a waveguide and is recorded as it passes by one or more microphones located inthe wave guide wall. After propagating down the ETT, the sound pulse isemitted through the distal tip of the ETT into the airway (or whereverin the body the tip of the ETT is located) and an acoustic reflectionpropagates back up the BIT to the wave guide for measurement by the samemicrophone(s). The amplitude and the polarity of the incident andreflected sound pulse are used to estimate the characteristics of theairway and the ETT, and thereby guide the MT placement or monitor theETT for patency.

As disclosed by Wodicka, et al., the acoustical properties of theairways of a respiratory system change dramatically over the audiblefrequency range. At very low frequencies, the large airway walls areyielding and significant wall motion occurs in response to intra-airwaysound. In this frequency range, the airways cannot be representedaccurately as rigid conduits and their overall response to sonic pulsesis predictably complex. At very high audible frequencies, the largeairway walls are effectively more rigid due to their inherent mass.However, one-dimensional sound propagation down each airway segmentcannot be ensured as the sonic wavelengths approach in size the diameterof the segment, and effects of airway branching are thought to increasein importance. There appears to be a finite range of frequencies betweenroughly 500 and 6,000 Hz where the large airways behave as nearly rigidconduits and the acoustical effects of the individual branching segmentsare not dominant. It is over this limited frequency range where thecomplicated branching network can be approximately represented as aflanged “horn” and where its composite acoustical properties reflect thetotal cross-sectional area of the airways.

Accordingly, there is a need for an improved method and system foracoustically sensing a leak in the seal between a tube or catheterwithin a body and the body cavity against which it is sealed and toassist the user in adjusting the system until the leak has beensubstantially sealed. In addition, there is a need for establishingsystem parameters to be used thereafter to maintain the system in anoperating state that will substantially prevent leakage, all using anoninvasive acoustic technique. However, in view of the prior art at thetime the present invention was made, it was not obvious to those ofordinary skill in the pertinent art how the identified needs could befulfilled.

IV. SUMMARY

A leak detection system and method for tube or catheter placement isdisclosed. The system and method of the present disclosure convenientlyutilize the microphone in the waveguide connected to the ETT to detectsounds indicative of leakage past the ETT cuff. Alternatively, anothermicrophone independent of the microphone used to guide placement of theETT may be used. The noninvasive system and method of the presentdisclosure are therefore able to assist the user in creating an adequateseal between the ETT and the trachea (or between any other tube orcatheter and a body cavity into which it has been inserted) and assistin maintaining the seal once it has been established. Furthermore, thesystem has no moving parts, and can be easily understood and operated byskilled clinicians.

According to one aspect of the present disclosure, the system may beconfigured for acoustically detecting the sounds caused by fluids (suchas air or other gases) leaking past a cuff sealing a tube or catheteragainst the walls of an anatomical conduit. Detection of these sounds,either by a human operator or by an automated system employing aprocessing device, can be used to warn a user of the system that a leakis occurring, and in other embodiments can automatically initiateadjustment of the system in order to stop the leak. For example, thesystem may include a microphone for detecting sounds in or near the tubeand for generating a first signal corresponding to the detected sound, aspeaker for creating an audible version of the first signal, where auser can listen to the audible version and determine if adjustments tothe leakage prevention cuff are needed.

In another particular embodiment, the system may include the microphonefor detecting sounds in or near the tube and for generating a firstsignal corresponding to the detected sound, and a processor configuredto receive the first signal and to discriminate between an expectedbaseline representing normal sounds in or near the tube and unexpectedsounds representative of leakage past the cuff, where the processorusing the first signal to report that a leak has been detected. Theprocessor may be further configured to detect that a leak is present andto then control an inflation device to automatically increase thepressure in the leak prevention cuff. In addition, the tube may beadapted to be coupled to a medical device, such as a mechanicalventilator, a breathing bag, an anesthesia machine, or an infusion pump.Further, a display may be provided in electronic communication with theprocessor.

In yet another illustrative embodiment, a method of acousticallydetecting a leak past a cuff sealing a tube to a body is disclosed. Themethod includes detecting a sound in or near the tube, and audiblypresenting the detected sound to a user of the tube for determination ofwhether a leak is present. In one aspect of this embodiment, the methodfurther includes applying the detected sound signal to a processor thatis configured to analyze the sound and detect the sound of a leak over abaseline expected sound profile. The method may also include causing theprocessor to operate an inflation device to renew the seal between thetube and the anatomical conduit if the processor detects a leak. In yetanother aspect of this method, the detected sound may be used as afeedback mechanism when pressurizing the cuff, such that when thedetected sound indicates that the leakage has stopped, the pressure ofthe cuff can be recorded and thereafter adjusted to maintain thepressure at that level.

Additional objects, features, and advantages of the present disclosurewill become apparent to those skilled in the art upon consideration ofthe following detailed description of a preferred embodimentexemplifying the best mode of carrying out the teachings of the presentdisclosure as presently perceived.

V. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatical view of a prior art system for determiningcharacteristics of an unknown system;

FIG. 2 is a diagrammatical view of a prior art two-microphone system fordetermining characteristics of an unknown system;

FIG. 3 is a diagrammatical view illustrating proper insertion of anendotracheal tube (ETT) into a trachea of a human body;

FIG. 4 is a diagrammatical view illustrating improper placement of theETT into an esophagus;

FIG. 5 is a diagrammatical view illustrating improper placement of anETT past a carina and into a right main bronchus;

FIG. 6 is a cross-sectional diagrammatical view of one embodiment leakdetection system;

FIG. 7 is a diagrammatical view of a particular illustrative embodimentof a leak detection method for tube or catheter placement; and

FIG. 8 is a flow diagram of a particular embodiment of a leak detectionmethod for placement of a tube or catheter.

VI. DETAILED DESCRIPTION

For purposes of promoting an understanding of the principles of themethod and system, reference will now be made to the embodimentillustrated in the drawings, and specific language will be used todescribe that embodiment. It will nevertheless be understood that nolimitation of the scope of the method and system is intended.Alterations and modifications, and further applications of theprinciples of the method and system as illustrated therein, as wouldnormally occur to one skilled in the art to which the method and systemrelates are contemplated, are desired to be protected. Such alternativeembodiments require certain adaptations to the embodiments discussedherein that would be obvious to those skilled in the art.

When it is desired to direct an object (such as a tube, catheter, orother medical device) into an unknown system, it is known to generate asound pulse within the tube or medical device and to receive thereflections of the pulse as they return from the unknown system, similarto the process used in sonar imaging. In the case of a system as shownin FIG. 1, a speaker transmits an incident sound pulse, P_(i) thattravels toward the unknown system. As the incident sound pulse, P_(i),enters the unknown system, a sound pulse is reflected back, P_(r), whichcan be received by the microphone. The reflected sound pulse, P_(r), canbe analyzed to determine various qualities of the unknown system,including the cross sectional area of the system. Furthermore, as theincident sound pulse P_(i) continues to propagate through the unknownsystem, additional reflections may occur. These subsequent reflectedsound pulses can indicate additional qualities of the unknown system,such as the depth of the system, and whether the cross sectional areachanges at all throughout that depth.

A two-microphone system is shown in FIG. 2, where the two microphonesare separated by a distance d. In the two-microphone system,determination can be made as to the direction of travel of a soundpulse, P_(i) or P_(r), by analyzing the difference between the instantin which the sound pulse is detected by the first microphone M1, and theinstant in which the sound pulse is detected by the second microphone,M2. For example, if a sound pulse is first detected by M1 and then byM2, the pulse is determined to be traveling away from the unknownsystem, and is thus a reflected pulse P_(r). In contrast, if a soundpulse is first detected by M2 and then M1, the pulse is determined to betraveling toward the unknown system.

The directional determination of the traveling sound pulse prevents themisreading of incident sound pulses that are reflected from the speakerend, SE, of the tube, such as P_(ir). For various reasons, an incidentsound pulse, P_(i), may be reflected from the speaker end, SE, of thetube, including the presence of a blockage in the tube, a wall at theend of the tube, or the attachment of another device (i.e. a mechanicalventilator) to the end of the tube. False readings can occur whenreflected sound pulse, P_(ir), travels past a single microphone, such asthat shown in FIG. 1. However, when two microphones are used, such as inthe system illustrated in FIG. 2, a determination of the direction oftravel of the reflected sound pulse, P_(ir), can eliminate thepossibility of a misreading.

Although the method and system described below relate to maintaining aseal between an endotracheal tube (ETT) and a portion of a respiratorysystem of a body, it should be understood that the system and methods ofthe present disclosure may be used to maintain a seal between gas orliquid filled tubes or catheters and other anatomical conduits orcavities.

As mentioned above, a method and system for guiding the positioning ofan

ETT is known in the art. For a description of a single microphone systemfor guiding the insertion of the ETT, and a more detailed description ofthe analysis and theory involved in determining the position of the ETT,reference can be made to U.S. Pat. No. 5,455,144 to Wodicka, et al.,previously incorporated by reference. For a description of atwo-microphone system for guiding the insertion of the ETT, and a moredetailed description of the analysis and theory involved in determiningthe position of the ETT, reference can be made to U.S. Pat. No.6,705,319 to Wodicka, et al., previously incorporated by reference.

Referring now to the drawings, FIGS. 3-5 illustrate insertion of an ETT10 into a human body 12. ETT 10 includes a hollow tube having a distalend 14 for insertion into body 12 and a connector 16 located outsidebody 12. Illustratively, ETT 10 is inserted into a mouth 18 of thepatient. A respiratory system 20 includes a trachea 22 which extendsbetween vocal folds 24 of a larynx and a first bifurcation known as acarina 26. Airways formed by carina 26 include a right primary bronchus28 and a left primary bronchus 30. Continuing farther down the airway,bronchial tubes branch into smaller and smaller tubes.

FIG. 3 illustrates proper insertion of ETT 10 into trachea 22 betweenvocal folds 24 and carina 26. For proper mechanical ventilation of thepatient, it is important that distal end 14 of ETT 10 is positionedproperly within trachea 22 between vocal folds 24 and carina 26 toprovide adequate ventilation to both lungs 32 and 34. An inflatable cuff35 provides a seal between the ETT 10 and the airway, as described ingreater detail hereinbelow.

Insertion of ETT 10 into the trachea 22 is sometimes a difficultprocedure. As illustrated in FIG. 4, it is possible for distal end 14 ofETT 10 to miss the entrance to trachea 22 and enter an esophagus 36leading to the stomach (not shown). Improper placement of ETT 10 intothe esophagus is most evident in a pre-hospital or emergency roomsetting which is characterized by high stress and limited time. Improperplacement of open distal end 14 of ETT 10 into the esophagus 36 preventsventilation of lungs 32 and 34.

Improper insertion of distal end 14 of ETT 10 past carina 26 will resultin ventilation of only right lung 32 or left lung 34. FIG. 5 illustratesimproper insertion of distal end 14 of ETT 10 past carina 26 and intoright main bronchus 28. Because right primary bronchus 28 is shorter,wider, and more vertical than left primary bronchus 30, the majority ofETT insertions past carina 26 tend to follow the right primary bronchus28. The speaker/microphone guidance systems disclosed in U.S. Pat. Nos.5,455,144 and 6,705,319 to Wodicka, et at, detect if ETT 10 isimproperly inserted into esophagus 36, right primary bronchus 28, orleft primary bronchus 30 and alert a user to the improper placement. Theapparatus can then be used to guide movement of UT 10 back into itsproper position within trachea 22.

According to some embodiments of the present disclosure, the Err 10 maybe equipped with a cuff 35 as shown in FIG. 6. The cuff 35, known to aperson having ordinary skill in the art, is coupled to a tubular portion204 of the ETT 10 near the distal end 14. In FIG. 6, the ETT 10 is showninserted into a body cavity, such as a trachea 22. The cuff 35 isconfigured to be a flexible member. In one form, the cuff 35 is formedin a substantially toroidal form, having any desired cross-sectionalshape such as circular, oval, square or rectangular, to name just a fewnon-limiting examples. Pressurizing the interior of the cuff 35 with agas or fluid can adjust an outer diameter (identified by referencenumeral 210) of the cuff 35 with respect to an inner diameter(identified by reference numeral 208), thereby determining the pressurewith which the cuff 35 presses against both the tubular portion 204 ofthe ETT 10 and the walls of the trachea 22. The inner portion of thecuff 35 is coupled to the outer surface of the tubular portion 204. Thecuff 35 can be permanently coupled to the tubular portion 204, e.g., bybeing molded to or glued to the tubular portion 204, or in other mannersthat will be apparent to those skilled in the art in view of the presentdisclosure.

The cuff 35 may be in communication with an inflation device 225. In oneembodiment, the inflation device 225 comprises a one-way valve 220 towhich a syringe 221(or other appropriate device) may be attached. Theinflation device 225 can be configured to inflate the cuff 35 for animproved sealing against the anatomical conduit such as the trachea 22.Syringe 221 contains a gas or fluid 222 that may be injected to, orwithdrawn from, the cuff 35 through the tube 224 by actuation of theplunger 226. Once inflated, the syringe 221 may be optionallydisconnected from the one-way valve 220. Other devices known in the artmay be used as an inflation device 225, such as a pump, for example.

The cuff 35, when properly pressurized, is configured to preventbackflow of air, or other fluids (e.g., blood, mucous, liquid andgaseous compounds, etc.), collectively referred to hereunder as air orother fluids, between the tubular portion 204 of the ETT 10 and thetrachea 22, or other anatomical structures, collectively referred tohereunder as anatomical conduits, with which the ETT 10 or other tubulardevice is used to transfer air or other fluids therein. Such a backflowis undesired in ventilation and other applications in which the air orother fluids are introduced through the ETT 10 to an anatomical conduit,as it is desired to maintain a positive pressure within the anatomicalconduit. In the case of an ETT 10 positioned within a trachea 22, thecuff 35 performs the further function of preventing the flow ofaccumulated fluids that may be proximal to the cuff 35 past the cuff 35and into the lungs. Such unintended flow can cause pneumonia in thepatient.

The undesirable passage of the air or other fluids between the cuff 35and the anatomical conduit generates vibrations. The vibrations cangenerate waves that can be sensed by a detection device that may includethe first microphone 76 and/or the second microphone 78. Themicrophone(s) 76, 78 may be coupled to an external speaker or headphonesthrough an appropriate optional amplifier so that a user can listen forthe sound made by the fluid leaking past the cuff 35. In one embodiment,the inflation device 225 is operated to increase the pressure in thecuff 35 until the user detects that the sound generated by the leakagepast the cuff 35 has stopped or substantially stopped. An appropriatepressure sensor of the cuff 35 (and/or the inflation device 225) maysense a cuff pressure and record the cuff pressure at this point in timeand adjustment of the cuff pressure using the inflation device 225 maybe made throughout the remaining time that the ETT 10 is inserted inorder to maintain the cuff 35 at that pressure. Such monitoring andmaintenance of the appropriate pressure may be done manually by theoperator, or under the control of a computer or other processing deviceas will be appreciated by those skilled in the art in view of thepresent disclosure. For example, an automated system may be used tomaintain the cuff 35 pressure at a set point, and that set point may bedetermined by acoustic feedback identifying the presence or absence ofsound leaking past the cuff 35.

In some embodiments, two microphones (such as those illustrated in FIGS.2 and 6), may be used in order to help identify the sounds indicative ofleakage past the cuff 35. As described hereinabove, two microphones 76,78 may be used to determine the direction of travel of a sound. Usingsuch techniques, the system may differentiate between sounds that arisefrom the machine (e.g., ventilator) end from those that arise from thepatient end. The system may use this information to verify that thesound identified as noise leaking past the cuff 35 is indeed propagatingin a direction coming from the cuff 35 to the microphones 76, 78 using atemporal analysis or other appropriate analysis.

In other embodiments, the cuff 35 can be initially filled to apredetermined pressure (such as a pressure recommended by themanufacturer of the ETT 10). Thereafter, the microphones 76, 78 can beused to monitor for a leak past the cuff 35 and, if detected, theinflation device 225 can be used to increase the pressure in the cuff 35until the leakage is heard to cease or substantially cease.

In other embodiments, the leak detection may also be automated, with adetection system configured to detect vibrations generated due to thebackflow of the air or other fluids. In other embodiments, the processormay have direct control of the operation of the inflation device 225 andcan automatically adjust the pressure in the cuff 202.

Referring to FIG. 7, a particular illustrative embodiment of a leakdetection system is depicted and generally designated 300. As describedabove, the ETT 10 may be inserted into the anatomical conduit, such as atrachea 22 and equipped with a cuff 35. The pressure of the cuff 35 canbe increased and decreased to adjust to an outer diameter of the cuff 35to press against the ETT 10 and the walls of the trachea 22. The system300 includes a processor 304 that is communication with a vibrationdetection device 80 configured to detect acoustic waves generated byvibrations caused by a leak of fluids between the cuff 35 and ananatomical conduit 22. In addition, the tube 10 may be adapted to becoupled via connector 16 to a medical device 90, such as a mechanicalventilator, a breathing bag, an anesthesia machine, or an infusion pump.A memory 306 of a computer 302 may be configured to store baselineexpected sound profile(s) 308. An analysis module 310 may be used todetermine whether signals received from the microphones 76, 78 of thevibration detection device 80 indicate a leak around the cuff 35 whencompared to the expected sound profiles 308. In addition, an outputdevice 312 may be in direct communication with the computer 302, wherethe output device 312 is able to render an audio alert, visual alert, orany combination thereof. For example, a cathode ray tube (CRT) display,liquid crystal display (LCD), light emitting diode (LED) display, plasmadisplay, or other display device that is accessible to the processor 304to display a visual rendering of the expected sound profiles 308 and thesignals received from the microphones 76, 78.

An inflation device 225 may be in communication with the cuff 35 viatube 224 and the computer 302. The sound profile(s) 308 and analysismodule 310 may be implemented in hardware, firmware, software, otherprogrammable logic, or any combination thereof. The memory 306 includesmedia that is readable by the processor 304 and that stores data andprogram instructions that are executable by the processor 304.

In operation, the sound profile exhibited by air or other fluids leakingpast the cuff 35 may be characterized, such as vibrations within adefined frequency range detected over a minimum window of time. Theprocessor 302 of the detection system 300 is programmed to analyze thesignals generated by one or more microphones 76, 78 of the vibrationdetection device 80, and to detect a sound pattern matching the knownleakage sound profile 308. In an alternative embodiment, a baseline isestablished for normal passage of the air or other fluids, i.e., absenceof a backflow of the air or other fluids caused by leakage past the cuff35, and a processor 304 of the detection system 300 is programmed toanalyze signals generated by at least one the microphone 76 or 78. Theprocessor 304 can then be programmed to recognize vibrations caused dueto the backflow of the air or other fluids, such vibrations being inaddition to the expected baseline vibrations. When the processor 304identifies the air or other fluids are leaking due to the backflow, theprocessor 304 can then provide an audio and/or visual alert to anoperator to take corrective actions.

A flow diagram of a particular embodiment of a leak detection method isdescribed in FIG. 8. At 400, a sound in or near a tube that is insertedin an anatomical conduit is detected using a microphone. The sound maybe generated from a speaker within the tube or acoustic waves generatedby vibrations caused by a leak of fluids between a cuff and ananatomical conduit. Moving to 402, the detected sound may be audiblypresented to an operator of the tube for determination of whether a leakaround a cuff of the tube is present. In addition, or alternatively, thedetected sound signal may be transmitted, at 404, to a processor that isconfigured to analyze the sound and detect the sound of the leak over abaseline expected sound profile. The processor is configured to operateand cause an inflation device to renew a seal between the tube and theanatomical conduit if the processor detects the leak, at 406. Thedetected sound may be used as a feedback mechanism when pressurizing thecuff, at 408, such that when the detected sound indicates that theleakage has stopped, a level of pressure of the cuff is recorded andthereafter adjusted to maintain the pressure at the level.

Although the system and method described is related to maintaining aseal around an ETT 10 within a respiratory system of a body, it isunderstood that the system and method of the present disclosure may beused to maintain seals around gas or liquid filled tubes or cathetersinto other body cavities or in various mechanical operations. The leakdetection system and method can be applied to a wide variety of clinicaltubes or catheters where maintenance of a seal therearound is required.

Although the teachings of the present disclosure have been described indetail with reference to certain embodiments, variations andmodifications exist within the scope and spirit of these teaching asdescribed and defined in the following claims:

What is claimed is:
 1. A leak detection system for tube placement, thesystem comprising: a tube; an inflatable cuff coupled to the tube; amicrophone at only one location coupled to the tube and configured todetect acoustic waves generated by vibrations from a passage of airbetween the inflatable cuff and an anatomical conduit when inserted inthe anatomical conduit; and a microprocessor having a memory and themicroprocessor coupled to the microphone and configured to compare theacoustic waves to a baseline expected sound profile stored in the memoryand determine that a leak around the inflatable cuff is present when theacoustic waves are in addition to the expected sound profile, thebaseline expected profile is established by detection of a frequencyrange over a duration of time, such that the expected baseline soundprofile defines an absence of a backflow of the air and other fluidscaused by leakage past the cuff.
 2. The leak detection system of claim1, further comprising an inflation device coupled to the inflatablecuff, wherein the inflation device is configured to increase a pressurein the inflatable cuff when leakage is detected to renew a seal betweenthe inflatable cuff and the anatomical conduit.
 3. The leak detectionsystem of claim 1, further comprising a pressure sensor in communicationwith the inflatable cuff.
 4. The leak detection system of claim 2,wherein the inflation device is coupled to the microprocessor andconfigured to automatically activate the inflation device to increasethe pressure in the inflatable cuff when leakage is detected.
 5. Theleak detection system of claim 2, wherein the microprocessor isconfigured to generate an alert when leakage is detected.
 6. The leakdetection system of claim 3, further comprising an external speakercoupled to the microphone.
 7. The leak detection system of claim 4,further comprising a display configured to visually display at least onebaseline expected sound profile stored in the memory and the detectedacoustic waves from the microphone.
 8. The leak detection system ofclaim 5, wherein the tube comprises a catheter.
 9. The leak detectionsystem of claim 1, wherein the inflatable cuff is coupled to a peripheryof a distal end of the tube.
 10. A leak detection system for tubeplacement, the system comprising: a tube; an inflatable cuff coupled tothe tube; a microphone at only one location configured to detectacoustic waves generated by vibrations from a passage of air between theinflatable cuff and an anatomical conduit; a microprocessor having amemory and the microprocessor coupled to the microphone and configuredto compare the acoustic waves to a baseline expected sound profilestored in the memory and determine that a leak around the inflatablecuff is present when the acoustic waves are in addition to the expectedsound profile, the baseline expected profile is established by detectionof a frequency range over a duration of time, such that the expectedbaseline sound profile defines an absence of a backflow of the air andother fluids caused by leakage past the cuff; and an inflation devicecoupled to the inflatable cuff.
 11. The leak detection device of claim10, further comprising a mechanical ventilator coupled to the tube. 12.The leak detection device of claim 10, wherein the anatomical conduitcomprises a trachea.
 13. The leak detection system of claim 10, whereinthe inflation device is configured to increase a pressure in theinflatable cuff when leakage is detected.
 14. The leak detection systemof claim 10, wherein the inflation device comprises a pump.
 15. The leakdetection system of claim 10, further comprising a pressure sensor incommunication with the inflatable cuff.
 16. The leak detection system ofclaim 10, wherein the inflation device is coupled to the microprocessorand configured to automatically activate the inflation device toincrease the pressure in the inflatable cuff when leakage is detected.17. The leak detection system of claim 10, wherein the microprocessor isconfigured to generate an alert when leakage is detected.
 18. The leakdetection system of claim 10, further comprising an external speakercoupled to the microphone.
 19. The leak detection system of claim 10,further comprising a display configured to visually display at least onebaseline expected sound profile and the detected acoustic waves from themicrophone.
 20. The leak detection system of claim 10, wherein the tubecomprises a catheter.